Windows: WinRAR/Rar.exe Writing Files to Startup Folder Locations

Alerts on WinRAR/Rar creating files under the Windows Startup folder, a common persistence attempt.

FreeReviewedSigma · High · v2

Product: windows
Category: file_event
Author: Swachchhanda Shrawan Poudel (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2025-07-16
Updated: 2026-07-31

ATT&CK techniques

Persistence → Priv Esc

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1547.001Registry Run Keys / Startup Folder
Priv Esc
- T1547.001Registry Run Keys / Startup Folder
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies WinRAR or Rar executing while creating/writing a file whose path contains the Windows Startup directory under the Start Menu Programs. Malicious use of Startup folders can provide persistence by launching attacker-controlled files when a user logs in. Detection relies on Windows file event telemetry that records the creating process image and the target filename/path.

Reporting behind it

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Windows: WinRAR/Rar.exe Writing Files to Startup Folder Locations

Pivot detection · T1547.001 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-winrar-rar-creating-files-in-startup-folder-paths-74a2b37d

title: "Windows: WinRAR/Rar.exe Writing Files to Startup Folder Locations"
id: 3b37b5d0-2353-419b-b1e3-d7e371c6dcfc
status: experimental
description: This rule identifies WinRAR or Rar executing while creating/writing a file whose path contains the Windows Startup directory under the Start Menu Programs. Malicious use of Startup folders can provide persistence by launching attacker-controlled files when a user logs in. Detection relies on Windows file event telemetry that records the creating process image and the target filename/path.
references:
  - https://github.com/mulwareX/CVE-2025-6218-POC
  - https://x.com/0x534c/status/1944694507787710685
  - https://www.welivesecurity.com/en/eset-research/update-winrar-tools-now-romcom-and-others-exploiting-zero-day-vulnerability/
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/file/file_event/file_event_win_winrar_file_creation_in_startup_folder.yml
author: Swachchhanda Shrawan Poudel (Nextron Systems), Huntrule Team
date: 2025-07-16
tags:
  - attack.privilege-escalation
  - attack.persistence
  - attack.t1547.001
logsource:
  category: file_event
  product: windows
detection:
  selection:
    Image|endswith:
      - \WinRAR.exe
      - \Rar.exe
    TargetFilename|contains: \Start Menu\Programs\Startup\
  condition: selection
falsepositives:
  - Unknown
level: high
license: DRL-1.1
related:
  - id: 74a2b37d-fea4-41e0-9ac7-c9fbcf1f60cc
    type: derived

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